You've retrieved the values from storage, you've then edit that value in-memory.
You'll then have to persist these changes, by writing them to the storage.
var storedNames = JSON.parse(localStorage.getItem("user_login_users"));
// remove an entry
var newStoredNames = storedNames.slice(0,1);
// or change an existing one.
newStoredNames[0].password="my_new_value";
// persist the changes:
localStorage.setItem("user_login_users", JSON.stringify(newStoredNames));
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…